@article{DAN_1989_304_6_a2,
     author = {V. V. Ostapenko},
     title = {Divergence of difference operators that are defined on an},
     journal = {Doklady Akademii Nauk},
     pages = {1295--1298},
     year = {1989},
     volume = {304},
     number = {6},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/DAN_1989_304_6_a2/}
}